<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <input type="text" v-bind:value='val' @input='handle'>
        <input type="text" v-bind:value='val' @input='val=$event.target.value'>
        <input type="text" v-model='val'>
        <p>{{val}}</p>
    </div>
    <script src="../vue.js"></script>
    <script>
        var vm = new Vue({
            el: '#app',
            data: {
                val: ''
            },
            methods: {
                handle: function(e) {
                    this.val = e.target.value
                }
            }
        })
    </script>
</body>

</html>